1:   

   2:  public class MockObj

   3:  {

   4:  prop a

   5:  prop b

   6:  prop c

   7:  prop d

   8:  }

   1:   

   2:  protected void gv_OnSorting(object sender, GridViewSortEventArgs e)

   3:  {

   4:  if (SortDirection == SortDirection.Ascending)

   5:  ((GridView)sender).DataSource = List.OfType().OrderBy(mo=> mo.GetType().GetProperty(e.SortExpression).GetValue(mo, null));

   6:  else

   7:  ((GridView)sender).DataSource = List.OfType().OrderByDescending(mo=> mo.GetType().GetProperty(e.SortExpression).GetValue(mo, null));

   8:  SortDirection = SortDirection == SortDirection.Ascending ? SortDirection.Descending : SortDirection.Ascending;

   9:  ((GridView)sender).DataBind();

  10:  }

   1:   

   2:  public DataTable GetSomeData(par1, par2...., string sortExpression)

   3:  {

   4:  var query = (//Linq query goes here )

   5:  // We want something like this which is not possible as of now

   6:  var query = (some query) (OrderBy SortExpression)

   7:  }

   1:   

   2:  public DataTable GetSomeData(par1, par2...., string sortExpression)

   3:  {

   4:  var query = (//Linq query goes here )

   5:  // We want something like this which is not possible as of now

   6:  var query = (some query) (OrderBy SortExpression)

   7:  }

   8:  public static Util

   9:  {

  10:  //Thanks to Ernesto for pointing out a small correction in method signature.

  11:  public static  IQueryable<TEntity> OrderBy(this IQueryable<TEntity> source, string sortExpression) where TEntity : class

  12:  {

  13:  var type = typeof(TEntity);

  14:  // Remember that for ascending order GridView just returns the column name and for descending it returns column name followed by DESC keyword

  15:  // Therefore we need to examine the sortExpression and separate out Column Name and order (ASC/DESC)

  16:  string[] expressionParts = sortExpression.Split(' '); // Assuming sortExpression is like [ColoumnName DESC] or [ColumnName]

  17:  string orderByProperty = expressionParts[0];

  18:  string sortDirection = "ASC";

  19:  string methodName = "OrderBy";

  20:  //if sortDirection is descending

  21:  if (expressionParts.Length > 1 && expressionParts[1] == "DESC")

  22:  {

  23:  sortDirection = "Descending";

  24:  methodName += sortDirection; // Add sort direction at the end of Method name

  25:  }

  26:  var property = type.GetProperty(orderByProperty);

  27:  var parameter = Expression.Parameter(type, "p");

  28:  var propertyAccess = Expression.MakeMemberAccess(parameter, property);

  29:  var orderByExp = Expression.Lambda(propertyAccess, parameter);

  30:  MethodCallExpression resultExp = Expression.Call(typeof(Queryable), methodName,

  31:  new Type[] { type, property.PropertyType },

  32:  source.Expression, Expression.Quote(orderByExp));

  33:  return source.Provider.CreateQuery(resultExp);

  34:  }

  35:  }

   1:   

   2:  public DataTable GetSomeData(par1, par2...., string sortExpression)

   3:  {

   4:  var query = (//Linq query goes here )

   5:  // We want something like this which is not possible as of now

   6:  var query = (some query)

   7:  return query.OrderBy(SortExpression).ToDataTable(rec => new object[] { query}));

   8:  }